摘要
在国网统招的电能表中,有相当数量的单相电能表要求L线和N线均能正确计量用电量,这两种计量分别采用锰铜分压和电流互感器采集电流大小。通常做法需要进行两路校准,这样制约了设备的使用效率。由此我们设计了一套校验系统只需要校准L线计量精度,则N线的计量精度也满足了要求,而实现此设计方案的前提就是需要精确测量N线电流互感器的负载电阻。本文采用Kelvin四线连接测量技术,通过设计高精度恒流源和测量电路,利用NI数据采集器和LabVIEW开发系统,实现PCB上被测电阻的阻值在线精密测量。该方案具有方法简单、生产效率高的特点,在实际生产中产生了良好的经济效益。
Nowadays there are a considerable number of state grid single-phase energy meters that require both phase line （L） channel and neutral line （N） channel to measure electricity consumption accurately. Shunt resistor and cur- rent transformer are used to implement current sampling. Normally each channel needs independent calibration to en- sure accuracy, however it restricts the efficiency of the equipment. Thus a new calibration system is designed, which only requires L channel to be calibrated and automatically achieves N channel＇s accuracy at the same time. Implemen- tation of this solution depends on the precision measurement of neutral line＇s current transformer load resistor. Online precision measurement of the resistor on PCB is implemented by using Kelvin 4-wire connection technology, designing high precision constant current source and measurement circuits, and applying NI data acquisition and LabVIEW de- velop system. This method is simple, easy to use, highly efficient, and has obtained good economic benefits.
出处
《电测与仪表》
北大核心
2014年第1期71-74,共4页
Electrical Measurement & Instrumentation
